This invention relates to the preparation of 3,3,3-trifluoropropene-1 via the reaction of a 1,1,1,3-tetrahalopropane and anhydrous hydrogen fluoride. More specifically. this invention relates to the preparation of 3,3,3-trifluoropropene-1 in which a simpler, improved catalyst than has been previously known in the art is utilized,
3'3,3-trifluoropropene-1 (TFP) is a chemical intermediate that has significant value as a commercial raw material. A primary example of the commercial value of TFP is its use in the preparation of fluorosilicone intermediates and such final products as fluorosilicone fluids and fluorosilicone rubber. Pierce et al., Industrial and Engineering Chemistry, 52(September, 1960), pp. 783-784, outline the preparation of the fluoroalkyl-substituted polydiorganosiloxane intermediates utilized in fluorosilicone materials, starting with TFP.
Haszeldine, U.S. Pat. No. 2,787,646. issued Apr. 2, 1957, discloses a process for the preparation of 3.3.3-trifluoropropenes from the fluorination of halogenpropenes. Suitable fluorinating agents disclosed are antimony trifluoride, antimony trifluorodichloride. The reaction occurs at low temperature in a liquid phase.
British Patent, G.B. No. 823,519, published Nov. 11, 1959, discloses the preparation of TFP from the reaction of 1,1,3-trichloropropene-1 with anhydrous hydrogen fluoride in the presence of a fluoride of vanadium, manganese, iron, cobalt, nickel, titanium, or silver at a temperature of at least 150.degree. C. This reference also teaches the impregnating of supports such as alumina, calcium oxide and aluminum fluoride with aqueous solutions of the metal fluorides. Also cited as catalysts are oxyfluorides and complex salts such as hexafluorotitanates.
Valicenti et al., U.S. Pat. No. 3,739,036, issued June 12, 1973, discloses a process for the preparation of TFP by contacting a halogenated hydrocarbon, such as 1,1,1,3-tetrachloropropane, with sodium fluoride at a temperature of from 400.degree. to 475.degree. C.
Ferstandig, U.S. Pat. No. 4,078,007, issued Mar. 7, 1978, and Ferstandig, U.S. Pat. No. 4,138,355, issued Feb. 6, 1979, disclose a process for the preparation of 3-chloro-1,1,1-trifluoropropane from the reaction of a 1,1,1,3-tetrahalopropane and liquid anhydrous hydrogen fluoride in the presence of a mixture of antimony pentahalide and antimony trihalide. The resultant 3-chloro-1,1,1-trifluoropropane is reacted with alkali to yield TFP.
Feiring, U.S. Pat. No. 4,220,608, issued Sept. 2, 1980, discloses the preparation of TFP by reaction of either 1,1,1,3-tetrachloropropane, 1,1,3-trichloropropene-1, or 3,3,3-trichloropropene-1 with anhydrous hydrogen fluoride under autogenous pressure in the presence of at least a catalytic amount of an organic monoamine, a salt of a monoamine, or an alkylene diamine.
Chromium oxyfluorides are cited in the art as catalysts for the preparation of TFP via the vapor phase reaction of halogenated hydrocarbons with anhydrous hydrogen fluoride. Ruh, U.S. Pat. No. 2,889,379, issued June 2, 1959, discloses a process in which a chromium oxyfluoride catalyst is used. Ruh presents an example of the preparation of a chromium oxyfluoride catalyst in which basic chromium fluoride and hydrated aluminum fluoride are slurried in aqueous hydrogen fluoride. Sugar is added to the slurry, and the slurry is dried to a cake. The cake is pelletized and contacted with oxygen for four hours at 550.degree. C. Zimmer et al., U.S. Pat. No. 4,465,786, issued Aug. 14, 1984, discloses a similar catalyst preparation. However, the preparation disclosed by Zimmer et al., involves the simultaneous fluorination of chromium and aluminum oxides in a manner similar to that taught by Ruh. Scherer et al., U.S. Pat. No. 3,752,850, issued Aug. 14, 1973, discloses fluorination of aliphatic hydrocarbons with anhydrous hydrogen fluoride at elevated temperatures in the presence of a catalyst with an empirical formula between EQU CrF.sub.1.5 O.sub.1.5 and CrF.sub.2 O.
This catalyst is prepared by fluorinating Cr(OH).sub.3 with anhydrous hydrogen fluoride at 400.degree. C.
Three references cite the activation of fluorination catalysts by addition of chlorine or chlorinated ethanes in the preparation of TFP. Japanese OPI No. 133,308/74, published Dec. 21, 1974, discloses the preparation of TFP from 1,1,1,3-tetrachloropropane and hydrogen fluoride in the presence of a fluorination catalyst, hexachloroethane and 1,1-dichloroethane being present in the reaction. Japanese OPI No. 144,509/78, published Dec. 15, 1978, discloses the preparation of TFP by the vapor phase reaction of 1,1,1,3-tetrachloropropane with hydrogen fluoride in the co-presence of a fluorination catalyst and hexachloroethane or 1,1-dichloroethane, the reactants being passed through a catalyst bed and then through a catalyst bed of vapor fluorination catalyst. U.S. Pat. No. 4,465,786, Zimmer et al., issued Aug. 14, 1984, discloses that fluorination catalysts can be activated by contact of the catalyst with chlorine or pentachloroethane.
Several references, not citing the preparation of TFP, cite the use of aluminum fluoride as a catalyst for the fluorination of halogenated hydrocarbon materials. U.S. Pat. No. 2,669,590, Miller et al., issued Feb. 6, 1954. discloses the use of essentially non-crystalline aluminum fluoride as a catalyst for the reaction of a two-carbon olefin containing the .dbd.CF.sub.2 group with hydrogen fluoride to yield fluorine-containing ethanes. U.S. Pat. No. 3,178,483, Christoph et al., issued Apr. 13, 1965, and U.S. Pat. No. 3,178,484, Christoph et al., issued Apr. 13, 1965, disclose the reaction of acetylene with hydrogen fluoride in the presence of beta- or gamma-aluminum fluoride to produce vinyl fluoride and 1,1-difluoroethane. Japanese Pat. No. 498,015, published Feb. 2, 1967, discloses the vapor-phase reaction of acetylene in the presence of amorphous aluminum fluoride to produce vinyl fluoride and 1,1-difluoroethane.
U.S. Pat. No. 3,650,987, Vecchio et al., issued Mar. 21, 1972, discloses the preparation of fluorinated ethanes using a catalyst consisting essentially of aluminum fluoride containing minor quantities of iron, chromium, and preferably nickel. The catalyst is prepared by adding iron or chromium compounds, and preferably also nickel compounds in a subdivided form to aluminum fluoride or alumina and then subjecting the composition thus obtained to an activation treatment by heating at 300.degree. to 550.degree. C. in a stream of nitrogen or air and then subjecting this composition to a fluorination treatment by heating at 200.degree. to 500.degree. C. Vecchio et al., discloses that the chromium and nickel are introduced preferably as a water solution of their salts. In a similar disclosure, British patent No. 1,283,386, Groppelli et al., published July 26, 1972, discusses a catalyst consisting of aluminum fluoride or fluorinated alumina with small quantities of manganese and chromium compounds.
U.S. Pat. No. 4,147,733, Fiske et al., issued Apr. 3, 1979, discloses the reaction of halogenated ethanes and ethylenes with hydrogen fluoride in the vapor phase in the presence of steam in the presence of an alumium fluoride, a nickel fluoride, or a chromium fluoride, or mixture thereof. The catalysts are thought to be oxyfluorides or hydroxyfluorides.
European Patent Publication No. 0 042 696, published Nov. 16, 1983, discloses the preparation of trifluoromethylpyridines using as a catalyst a fluoride of aluminum, chromium, iron, nickel, manganese, or cobalt. The Patent Publication states that it is preferred to charge a metallic oxide, chloride, hydroxide, or carbonate and to convert it into a fluoride with anhydrous hydrogen fluoride.
Japanese OPI No. 16,943/85, published Jan. 28, 1985, discloses the preparation of fluoromethane by the vapor reaction of methyl chloride and hydrogen fluoride in the presence of chromium fluoride and aluminum fluoride.
European Patent Publication No. 0 074 069, published Jan. 8, 1986, discloses the preparation of chlorofluoromethylbenzene using as a catalyst an aluminum fluoride carrying salts of iron, bismuth, tin, as well as chromium oxide or partially fluorinated chromium oxide carrying an alkali metal fluoride. The aluminum fluoride is immersed in an aqueous solution of the salt to be carried. After immersion the aluminum fluoride is heated to a temperature from 100.degree. to 150.degree. C. and preferably treated with hydrogen fluoride under reaction conditions.
The preparation of TFP from 1,1,1,3-tetrachloropropane, using HF as the fluorinating agent is at least a two-step process where, in addition to a fluorination reaction, dehydrohalogenation of the propane to a propene must occur. Thus, expansion of the art to fluorination of chlorinated hydrocarbons in general may be inappropriate.
Nowhere in the art is there demonstrated or suggested a catalyst for the preparation of 3,3,3-trifluoropropene-1 which is produced by mechanical mixing. in the absence of water, of aluminum fluoride and a transition metal compound, the transition metal compound being converted to a transition metal fluoride upon contact with anhydrous hydrogen fluoride.